Drywall Calculator
Work out how many drywall or plasterboard sheets you need for your walls and ceiling.
Board both sides of a stud wall? Double the wall length. Check local rules for fire-rated or moisture-resistant board in kitchens, bathrooms and garages.
About this tool
Enter the total length and height of the walls, any ceiling area and the area of doors and windows. Choose your sheet size to see how many sheets of drywall (plasterboard, gypsum board) to buy, including a waste allowance.
Frequently asked questions
Divide the area to cover by the area of one sheet and add 10–15% for cuts. A 20 m run of 2.5 m walls (50 m²) minus 4 m² of doors and windows needs about 18 sheets of 1.2 × 2.4 m plasterboard.
Subtract large openings like doors and big windows, but not small ones — the offcuts around small openings are rarely usable, so the waste allowance covers them.
Larger sheets (4 × 12 ft or 1.2 × 2.7 m) mean fewer joints to tape and fill, but they are heavier and harder to carry. Standard 4 × 8 ft or 1.2 × 2.4 m sheets suit most DIY jobs.
For a new stud partition, yes — enter the wall length twice (or double it). For existing masonry walls you only board the room side.
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